Acanthamoeba encephalitis: A Case Report and Review of Therapy

Abstract

Background:Acanthamoeba is a rare cause of encephalitis yet is associated with high mortality. Treatment protocols vary greatly and generally include combination therapy across a wide spectrum of antiinfective classes.Case Description:A 63-year-old male who underwent renal transplantation presented 6 months after transplantation with depressed level of consciousness. Imaging of the head with computerized tomography showed an enhancing lesion suspicious for brain abscess. Biopsy of the lesion showed Acanthamoeba cysts. The patient was treated with sulfadiazine, fluconazole, flucytosine, azithromycin, and miltefosine but without success. We review recently published cases of Acanthamoeba encephalitis with an emphasis on treatment protocols and outcomes.Conclusion:Free-living protozoans such as Acanthamoeba are ubiquitous in the environment and should be suspected in immunosuppressed persons who present with central nervous system findings and brain abscess. Biopsy is critical to establish the etiology so that appropriate combination therapy can be deployed.

Twenty Years of Acanthamoeba Diagnostics in Austria

“…The first clearly identified human case of Acanthamoeba GAE occurred in an Amercian patient with Hodgkin's disease (Jager and Stamm 1972 ) and the first case of GAE in an AIDS patient was recorded in 1986, also in the USA (Wiley et al 1987 ). Since then, several hundred GAE cases have been reported worldwide (reviewed in Marciano-Cabral and Cabral 2003 ; Martinez and Visvesvara 1997 ; Zamora et al 2014 ). In 1990, it became apparent that another free-living amoeba can cause GAE, namely Balamuthia mandrillaris , which had been isolated from the brain of a mandrill from the San Diego zoo (Visvesvara et al 1990 ) and was described as a new species in a new genus (Visvesvara et al 1993 ).…”

Fatal Granulomatous Amoebic Encephalitis Caused by Acanthamoeba in a Patient With Kidney Transplant: A Case Report

“…Aside from the well known Acanthamoeba keratitis associated with the use of contaminated contact lenses in the presence of microabrasions of the cornea, granulomatous amoebic encephalitis (GAE) is being recognized more frequently, especially with the growing population of immune-compromised hosts [ 3 ]. As such, GAE is now being diagnosed at the time of acute illness presentation, rather than at post mortem examination [ 4 , 5 ]. Up to 80% of the population is seropositive to various Acanthamoeba spp [ 6 ], but only a minority develop clinically significant illnesses.…”

“…Diagnosis is usually only confirmed with brain biopsy. This can delay the diagnosis and commencement of treatment and may contribute to the subsequent fatal outcome, particularly in the immune-compromised patients [ 2 , 4 , 6 ].…”

Fatal Acanthamoeba Encephalitis in a Patient With a Total Artificial Heart (Syncardia) Device

“…Although Acanthamoeba encephalitis is believed to primarily affect immunocompromised hosts such as transplant recipients, it has also been reported to occur in immunocompetant patients [ 7 , 8 ]. A review of 18 cases in the literature since 2002 noted 83% (15/18) were males, and 61% (11/18) had identifiable underlying immunosuppressive conditions [ 9 ]. The incubation period is not known but is postulated to be >10 days and can span several weeks to months [ 7 , 10 ].…”